The reason why some reports are only one page, is that SEMRush doesn't have any data for them on keywords, ads or competitors. You can verify this by typing the domain directly into SEMRush.
Usually the one page reports occur when a business that advertised in the past has stopped advertising or at least that's what SEMRush thinks.
Take a look at this screenshot and notice how the graph goes down to zero.
I also compared with SpyFu and I don't see any of their ads in recent serp cache's...